In the applet below, the masses of the small bodies are not all equal. Therefore, they are not evenly spaced around the central body. The smaller bodies (shown in blue) tend to be clumped together whereas the more massive bodies (shown in white) are spaced out. The mass per unit distance is approximately constant (although that is not how the spacings were derived). Also, the radii are not exactly the same. This is required in order to have all the bodies orbit at the same speed. But, the differences in radii are so small that it is not visually obvious.